DE112016006013T5 - Method for producing a metal-carbon fiber composite material - Google Patents

Abstract

A method for producing a metal-carbon fiber composite material comprises the steps of obtaining a coated film (12) having a carbon fiber layer (11) on a surface (10a) of a metal foil (10) by applying a coating liquid (5) Carbon fibers (1), etc., formed on the surface (10a) of the metal foil (10) with a gravure printing device (20); Forming a laminate in which a plurality of coated films (12) are laminated; and integrally joining the coated films (12) by heating while pressurizing the laminate in a laminating direction of the coated films (12). The shape of a cell (22) of a peripheral surface (21a) of a gravure roll (21) of the gravure coater (20) is a cup shape, and a diameter of a circle inscribed in a mouth shape of the cell (22) is related to the 1,2- times or more of the average fiber length.

Description

Technical area

The present invention relates to a process for producing a metal-carbon fiber composite material and a process for producing an insulating substrate.

In this specification and the appended claims, the term "aluminum" is used to refer to both pure aluminum and an aluminum alloy, unless otherwise specified, and analogously the term "copper" is used to refer to both pure copper and a copper alloy unless otherwise specified.

A vertical direction of an insulating substrate according to the present invention is not limited. In the present specification and the appended claims, however, for the purpose of facilitating understanding of the configuration of the insulating substrate, the mounting surface side of the insulating substrate on which a heat generating element is mounted is referred to as the upper side of the insulating substrate, and the opposite side of the substrate is referred to as the lower side of the insulating substrate.

Technical background

As a material with improved heat dissipation from metal such as aluminum and controlled linear expansion coefficient, an aluminum-carbon material composite is investigated.

As a method for producing this composite material, there are known a method in which carbon fiber as a carbon material is placed in molten aluminum and stirred and mixed (molten metal stirring method), a method of pressing molten aluminum into a hollow carbon molded body (molten metal forging method) Method in which aluminum powder and carbon powder are mixed and heated under pressure (powder metallurgical method), and a method in which aluminum powder and carbon powder are mixed and extruded (powder extrusion method).

However, with these methods, since molten aluminum or aluminum powder is used, the manufacturing work was complicated and the production equipment was large.

Japanese Unexamined Patent Publication No. 59-76840 (Patent Document 1) discloses a method of producing a reinforced metal material by forming a pre-molded product by bonding and bonding an inorganic whisker to a metal surface made of a thin metal sheet with an organic binder. and then heating and pressurizing a plurality of pre-formed products in laminated form.

Furthermore, this discloses Japanese Patent No. 5150905 (Patent Document 2) discloses a method of producing a metal-based carbon fiber composite material as a metal-carbon fiber composite material. In the process, carbon fibers are mixed with an organic binder and a solvent to produce a coating mixture. Subsequently, the coating mixture is adhered to a sheet-shaped or foil-shaped metal carrier to form a preform film (coated film). Thereafter, a plurality of preformed films are stacked to form a laminate. This heats and pressurizes the laminate to integrate the preformed films into one another.

Apart from the above documents that are Japanese Patent No. 5145591 (Patent Document 3) and Japanese Unexamined Patent Publication No. 2015-25158 (Patent Document 4) are known as further documents disclosing a method of producing a metal-carbon fiber composite material.

In the manufacturing method disclosed in Patent Documents 2 to 4, a metal-carbon fiber composite material is obtained by integrally joining a plurality of metal layers and carbon fiber layers in an alternately layered state.

Documents of the prior art

Patent document

• Patent Document 1: Japanese Unexamined
• Patent Publication No. 59-76840
• Patent Document 2: Japanese Patent No. 5150905
• Patent Document 3: Japanese Patent No. 5145591
• Patent Document 4: Unexamined Japanese
• Patent Publication No. 2015-25158.

PRESENTATION OF THE INVENTION

Object of the invention

Thus, in the method of producing a composite material in the above-mentioned Patent Document 1, when the inorganic whisker layer bonded or bonded to a metal surface of a thin metal plate is too thick, the metal of the thin metal plate can not sufficiently into the inorganic whiskers Cavities are formed in the inorganic Whsiker layer, and the thin metal plates disposed on both sides of the inorganic metal layer are not firmly joined to each other. For these reasons, the strength of the composite material was low.

The composite materials disclosed in Patent Documents 2 to 4 had the following disadvantages.

It is noted that in this specification, in a composite, a plane perpendicular to a lamination direction of a metal layer and a carbon fiber layer is referred to as "a plane of a composite material," and a plane direction perpendicular to the lamination direction of the metal layer and the carbon fiber layer is referred to as "plane direction a composite material "is called.

In a composite material, physical properties of the composite material, e.g. a linear expansion coefficient and a thermal conductivity, in the fiber direction (that is, the orientation direction of the carbon fiber) in the plane of the composite material and in a direction perpendicular thereto are significantly different from each other if fiber directions of the carbon fibers in a carbon fiber layer are aligned in a direction within a plane of the composite material, as in cases where the carbon fibers are aligned in one direction. Therefore, there was a disadvantage in that the composite material was easily distorted when the composite material was heated.

Under these circumstances, it is conceivable to form a laminate by laminating a plurality of preform films so that fiber directions of carbon fibers become alternately perpendicular.

However, in this method, the preform films must be laminated while taking into account the fiber directions of the carbon fibers, making the lamination process difficult. Moreover, it has been difficult to match the physical properties (eg, the linear expansion coefficient) in the oblique direction (eg, 45 degree direction) with respect to the fiber direction of the carbon fiber in the plane of the composite material equal to the physical properties of the carbon fiber in the fiber direction and a direction perpendicular thereto interpreted.

The present invention has been made in view of the above technical background, and an object is to provide a method for producing a metal-carbon fiber composite material capable of balancing physical properties of the composite material in a plane direction and a method of manufacturing an insulating material.

The other purposes and advantages of the present invention will become apparent from the following preferred embodiments.

Means of solving the task

1. [1] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials, wobei das Verfahren die folgenden Schritte umfasst:
   • Erhalten einer beschichteten Folie, bei der eine Kohlenstofffaserschicht auf einer Oberfläche einer Metallfolie durch Aufbringen einer Beschichtungsflüssigkeit gebildet wird, die Kohlenstofffasern, ein Bindemittel, und ein Lösungsmittel für das Bindemittel in einem gemischten Zustand enthält, auf die Oberfläche der Metallfolie mit einer Tiefdruckbeschichtungsvorrichtung, die mit einer Tiefdruckwalze versehen ist, bei der eine Reihe von Zellen auf einer Umfangsfläche davon gebildet sind;
   • Bilden eines Laminats in einem Zustand, bei dem eine Vielzahl von beschichteten Folien laminiert ist; und
   • einstückiges Fügen der beschichteten Folien durch Erhitzen des Laminats, um das Bindemittel aus dem Laminat zu entfernen, und Erhitzen des Laminats, während das Laminat in einer Laminierungsrichtung der beschichteten Folien mit Druck beaufschlagt wird,
   • wobei eine Form der Zelle der Tiefdruckwalze eine Becherform ist und ein Durchmesser eines Kreises, der einer Mündungsform der Zelle einbeschrieben ist, auf das 1,2-fache oder mehr einer durchschnittlichen Faserlänge der Kohlenstofffasern eingestellt wird.
2. [2] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials nach dem oben genannten Punkt 1, wobei der Schritt des Erhaltens der beschichteten Folie einen Schritt des Entfernens des Lösungsmittels aus der Kohlenstofffaserschicht umfasst, die auf der Oberfläche der Metallfolie gebildet wird.
3. [3] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials nach dem oben genannten Punkt 1, wobei der Schritt des Erhaltens der beschichteten Folie einen Schritt des Entfernens des Lösungsmittels aus der Kohlenstofffaserschicht, die auf der Oberfläche der Metallfolie gebildet ist, umfasst, ohne die Oberfläche der Kohlenstofffaserschicht einer Streichnivellierungsverarbeitung zu unterziehen.
4. [4] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials nach einem der oben genannten Punkte 1 bis 3, wobei in dem Schritt des einstückigen Fügens der beschichteten Folien das Bindemittel von dem Laminat während des Erhitzens des Laminats entfernt wird, so dass eine Temperatur des Laminats auf eine Temperatur ansteigt, bei der die beschichteten Folien einstückig gefügt werden.
5. [5] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials nach einem der oben genannten Punkte 1 bis 4, wobei die Form der Zelle zumindest eine Form ausgewählt aus der Gruppe bestehend aus einem Gitterform, einer Pyramidenform, einer sechseckigen Form, und einer kreisrunden Form ist.
6. [6] Verfahren zur Herstellung eines Metall-Kohlenstofffaser-Verbundmaterials nach einem der oben genannten Punkte 1 bis 5, wobei die Metallfolie eine Aluminiumfolie und/oder eine Kupferfolie ist.
7. [7] Verfahren zur Herstellung eines Isolierungssubstrats mit einer Vielzahl von Isolierungssubstrat-Bestandteilschichten, die in einem laminierten Zustand zu integrieren sind, wobei zumindest eine Bestandteilschicht der Vielzahl von Bestandteilschichten aus einer Metall-Kohlenstofffaser-Verbundmaterial hergestellt ist, und das Verbundmaterial durch ein Verfahren zur Herstellung des Metall-Kohlenstofffaser-Verbundmaterials nach einem der oben genannten Punkte 1 bis 6 hergestellt wird.

The present invention provides the following means.

1. [1] A method of producing a metal-carbon fiber composite material, the method comprising the steps of:
   • Obtaining a coated film in which a carbon fiber layer is formed on a surface of a metal foil by applying a coating liquid containing carbon fibers, a binder, and a solvent for the binder in a mixed state, to the surface of the metal foil with a gravure coater coated with a gravure roll in which a series of cells are formed on a peripheral surface thereof;
   • Forming a laminate in a state where a plurality of coated films are laminated; and
   • integrally joining the coated films by heating the laminate to remove the binder from the laminate, and heating the laminate while pressurizing the laminate in a direction of lamination of the coated films,
   • wherein a shape of the cell of the intaglio roll is a cup shape and a diameter of a circle inscribed in a mouth shape of the cell is set to be 1.2 times or more an average fiber length of the carbon fibers.
2. [2] A method of producing a metal-carbon fiber composite material according to the above-mentioned 1, wherein the step of obtaining the coated film comprises a step of removing the solvent from the carbon fiber layer formed on the surface of the metal foil.
3. [3] A method of producing a metal-carbon fiber composite material according to the above-mentioned 1, wherein the step of obtaining the coated film comprises a step of removing the solvent from the carbon fiber layer formed on the surface of the metal foil, without the Surface of the carbon fiber layer of a strike leveling processing.
4. [4] The method of producing a metal-carbon fiber composite material according to any one of the above-mentioned 1 to 3, wherein in the step of integrally joining the coated films, the binder is removed from the laminate during heating of the laminate so that a temperature of the laminate Laminates to a temperature at which the coated films are joined in one piece.
5. [5] The process for producing a metal-carbon fiber composite material according to any one of the above 1 to 4, wherein the shape of the cell is at least one shape selected from the group consisting of a lattice shape, a pyramid shape, a hexagonal shape, and a circular shape is.
6. [6] A method of producing a metal-carbon fiber composite material according to any one of items 1 to 5 above, wherein the metal foil is an aluminum foil and / or a copper foil.
7. [7] A method of manufacturing an insulating substrate having a plurality of insulating substrate constituent layers to be integrated in a laminated state, wherein at least one constituent layer of the plurality of constituent layers is made of a metal-carbon fiber composite material, and the composite material by a method of Preparation of the metal-carbon fiber composite material according to one of the above items 1 to 6 is produced.

Effects of the invention

The present invention has the following effects.

In the above [1], by performing the steps of applying a coating liquid to a surface of a metal foil, forming a laminate in a state where a plurality of coated foils are laminated, and integrally joining the coated foils by pressurizing and heating of the laminate, a metal-carbon fiber composite material can be mass-produced in a cost-effective manner.

Further, by removing the binder from the laminate, the thermal conductivity of the obtained composite material can be reliably increased.

Further, by a configuration such that the coating apparatus for applying a coating liquid to the surface of the metal foil is the gravure coater, the cell shape of the gravure roll of the gravure coater is a cup shape, and the diameter of the circle inscribed in the mouth portion of the row is set to the 1,2- Fache or more is set to an average fiber length of the carbon fiber, a carbon fiber layer is formed on the surface of the metal foil so that the fiber directions of the carbon fibers in the surface of the metal foil become random. For this reason, the physical properties of the composite material in the plane direction can be compensated. In addition, it is not necessary to consider the fiber directions of the carbon fibers in the formation of the laminate, so that the physical properties of the composite material in the plane direction can be easily compensated.

In the aforementioned item [2], by removing the solvent from the carbon fiber layer, it is possible to satisfactorily integrate the coated films in the step of integrally joining the coated films.

In the above-mentioned point [3], the fiber directions of the carbon fibers in the carbon fiber layer can be kept in a statistical state by not subjecting the surface of the carbon fiber layer to doctoring processing. As a result, the uniformity of the physical properties of the composite material in the plane direction can be reliably obtained.

In the above-mentioned point [4], the production of the composite material can be easily performed by removing the binder from the laminate during the heating of the laminate, so that the temperature of the laminate rises to a temperature at which the coated films are integrally joined ,

In the above-mentioned point [5], the shape of the cell is at least one shape selected from the group consisting of a lattice shape, a pyramid shape, a hexagonal shape, and a circular shape. For this reason, the carbon fiber layer can be formed on the surface of the metal foil so that the fiber directions of the carbon fibers in the surface of the metal foil become reliably random. As a result, the uniformity of the physical properties of the composite material in the plane direction can be reliably obtained.

In the above-mentioned point [6], since the metal foil is an aluminum foil and / or a copper foil, a composite material having high heat conductivity can be reliably obtained.

In the above-mentioned point [7], an insulating substrate having high reliability against temperature changes such as e.g. a cold / warm cycle are produced.

list of figures

• 1 FIG. 10 is a flowchart showing a method of manufacturing a metal-carbon fiber composite material according to an embodiment of the present invention.
• 2 Fig. 10 is a schematic diagram illustrating steps for obtaining a coated film.
• 3A Fig. 10 is a plan view illustrating an arrangement state of lattice forming cells on a peripheral surface of a gravure roll 21;
• 3B Fig. 16 is a perspective view showing the shape of the grid molding cell 3A represents;
• 4A Fig. 12 is a plan view illustrating an arrangement state of pyramidal cells on a peripheral surface of the gravure roll;
• 4B is a perspective view showing the shape of the pyramidal cell 4A represents;
• 5A Fig. 10 is a plan view illustrating an arrangement state of hexagon-shaped cells in a peripheral surface of a gravure roll;
• 5B Fig. 12 is a perspective view showing the shape of the hexagonal shaped cell 5A illustrated;
• 6A Fig. 10 is a plan view illustrating an arrangement state of circular cells on a peripheral surface of a gravure roll;
• 6B is a perspective view showing the shape of the circular cell 6A represents;
• 7A Fig. 10 is a side view of a cell in a case where the bottom surface of the cell has a flat shape;
• 7B Fig. 10 is a side view of the cell in a case where the bottom surface of the cell has a concave conical shape;
• 7C Fig. 12 is a side view of the cell in a case where communication ports are provided on the inner peripheral side surface of the cell;
• 8th Fig. 15 is a perspective view of a cell in a case where communication ports are provided on the inner peripheral side of the cell;
• 9 Fig. 12 is a perspective view when a strip member of the coated film has been cut to length;
• 10 Fig. 12 is a schematic side view of a laminate formed by laminating a plurality of coated films;
• 11 Fig. 12 is a schematic view for explaining a step of integrally sintering coated films;
• 12 Fig. 10 is a diagram (graph) showing an example of a temperature curve at the time of heating a laminate in the step of holistically sintering coated films;
• 13 Figure 3 is a schematic side view of a composite material of this embodiment obtained by integral sintering of coated films;
• 14 Fig. 15 is a perspective view of a composite material showing various directions defined by a composite material of this embodiment;
• 15 is a side view of an insulating substrate.

EMBODIMENT FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

As in 1 That is, a process for producing a metal-carbon fiber composite according to an embodiment of the present invention includes a step S1 of obtaining a coated film, a step S2 of forming a laminate, and a step S3 of integrally sintering the coated films. These steps are performed in this order.

Step S1 of obtaining a coated film is a step of obtaining a tape-like strip member 12A of the coated film 12 (ie a tape-like, long-coated film 12 ), as detailed in 2 described. In other words, this step S1 is a step of obtaining a stripe element 12A the coated film 12 in which a carbon fiber layer 11 made from a coating liquid 5 on the surface 10a of the strip member 10a of the metal foil 10 is formed by applying the coating liquid 5 on the surface 10a of the strip element 10A the metal foil 10. The coating liquid 5 is a mixture that is a carbon fiber 1 , a binder 2 , and a solvent 3 for the binder 2 in a mixed state.

Further, step S1 includes obtaining the coated film 12 a step S1a of removing the solvent 3 from the carbon fiber layer 11 on the surface 10a of the strip element 10A the metal foil 10 is formed (see 1 ).

As in 10 2, step S2 of forming a laminate is illustrated 15 a step of forming a laminate 15 in a state where a variety of coated films 12 be laminated.

As in 11 is shown, step S3 is the holistic sintering of the coated films 12 a step of holistic sintering of the coated films 12 by heating while the laminate 15 in the lamination direction of the coated films 12 (ie in the thickness direction of the laminate 15 ) is pressurized. This step SS3a includes a step of removing the binder 2 from the laminate 15 by heating the laminate 15 (please refer 1 ).

Step S3 of the integral sintering of the coated films 12 corresponds to a preferred example of the step of integrally joining the coated films 12 as stated in the claims.

The metal-carbon fiber composite material 17 According to this embodiment, a composite material that includes a metal and carbon fibers used as matrix means 1 as a material to be connected to the metal (matrix). In other words, this composite material can 17 be considered as a metal matrix composite material containing carbon fibers 1.

As in 13 shown is the composite material 17 obtained in this embodiment, a composite material in which a metal layer of a metal foil 10 and a carbon fiber layer 11 mainly made of carbon fibers 1 is formed to be sintered holistically in an alternately laminated manner. Part of the metal of the metal foil 10 is introduced into the carbon fiber layer 11. In this composite material 17, the metal corresponds to the matrix, and the carbon fiber 1 corresponds to the material to be bonded to the metal (matrix).

This composite material 17 may suitably be used as a material of at least one constituent layer among the plurality of insulating substrate constituent layers 51 to 55, which may be the one described in U.S. Pat 15 represent isolation substrate 50.

The insulating substrate 50 is used as a substrate of an electronic component such as a substrate of a power module. The insulating substrate 50 is formed by a wiring layer 51, a first stress buffer layer 52, a ceramic layer (insulation layer) 53, a second stress buffer layer 54, and a metal cooling layer 55 as a plurality of constituent layers. These constituent layers 51 to 55 are integrally joined by a predetermined joining means such as soldering in a state in which the wiring layer 51, the first stress buffer layer 52, the ceramic layer 53, the second stress buffer layer 54, and the cooling layer 55 sequentially from above laminated down.

The mounting surface 50a of the insulating substrate 50 is configured to mount a heat generating element 56 (indicated by a 2-dot chain line), e.g. an electronic element in a state of being joined by soldering or the like. The mounting surface 50 a is formed by the upper surface of the wiring layer 51.

The cooling layer 55 is a layer for cooling the heat generating element 56 and includes, for example, a plurality of heat dissipating fins 55a that are cooling elements (including heat radiating elements). Generally, the cooling layer 55 is made of aluminum or copper.

In the composite material 17 In this embodiment, the linear expansion coefficient in the plane direction may be set to an intermediate value between the linear expansion coefficient of metal and the coefficient of linear expansion of ceramics. Therefore, it is preferable in the insulating substrate 50 that, in particular, the first and / or the second stress buffer layers 52 and 54 under these constituent layers 51 to 55 are penetrated by the composite material 17 this embodiment is formed.

The composite material 17 This embodiment can be considered as a metal matrix composite reinforced with carbon fibers 1 and having a high elastic modulus. For this reason, it may be suitably used as a material for an element to have a high mechanical strength.

Next, each step will be described in detail.

<Step S1 of obtaining the coated film 12 >

The coating liquid 5 which is used in this step S1 is obtained as follows, for example. As in 2 are shown a large amount of carbon fibers 1, a binder 2 , and a solvent 3 for the binder 2 placed in a mixing tank 41, and they are stirred and mixed with a stirring and mixing device 42. This will become a coating liquid 5 get that the carbon fibers 1 , the binder 2 and the solvent 3 in a mixed state. At this time, if necessary, a dispersant, a defoamer, a surface conditioner, a viscosity modifier, etc. may be added to the mixing vessel and stirred and mixed therein.

The stirring and mixing device 42 is not specifically limited, and a stirrer-type stirring device, a planetary mixer, a homodisor, a ball mill, etc. may be used.

The specific explanation of the carbon fibers 1 , the binder 2, and the solvent 3 will be described later.

As a coating device for applying the coating liquid 5, a gravure coater (e.g., a gravure coater) 20 is used.

The gravure coating device 20 In particular, a direct gravure coating apparatus (eg, a direct gravure coater) is provided with a gravure roll 21, a backup roll 23, a coating liquid applying means 25 for adhering the coating liquid 5 to the peripheral surface 21a of the gravure roll 21, etc. On the entire peripheral surface 21a of the gravure roll 21 is a large number of cells (recesses) 22 provided in an orderly manner (see 3A . 4A . 5A and 6A ). A partition 21b is between adjacent cells 22 formed, and every cell 22 is separated by this partition 21b. The back-up roll 23 is disposed so as to face the gravure roll 21.

The coating liquid applying means 25 is provided with a coating liquid tank 26 containing the coating liquid 5 in this embodiment, the coating liquid contains and is set up 5 on the peripheral surface 21a of the gravure roll 21 apply by the gravure roll 21 is rotated about its central axis in a state in which a part of the circumferential direction of the peripheral surface 21a of the gravure roll 21 is immersed in the coating liquid 5 in the tub 26. The carbon fibers 1 in the coating liquid 5 in the tub 26 are in the coating liquid 5 dispersed so that their fiber directions are statistically distributed.

In the gravure coating apparatus 20 , in the 2 is shown, the unwound from the unwinding roll 27 a strip element 10A the metal foil 10 wound up by the winding roller 27b after having passed therethrough the intaglio roller 21 and the back-up roller 23 and the inside of the drying oven 28 as a drying device at a predetermined supply rate approximately in the horizontal direction.

The feeding direction F of the strip element 10A the metal foil 10 is on the longitudinal direction of the strip element 10A the metal foil 10 set. A direction parallel to the feeding direction F is the coating direction of the coating liquid 5 on the surface 10a of the strip member 10A of the metal foil 10 by the gravure coater 20 (specifically, the intaglio roll 21 of the gravure coater 20 ).

In this embodiment, the gravure roll is 21 on the lower side of the strip element 10A the metal foil 10 arranged such that it the strip element 10A the metal foil 10 completely traverses in the width direction, and the back-up roll 23 is on the upper side of the strip member 10A of the metal foil 10 arranged so that they are the strip element 10A the metal foil 10 completely in the width direction. Therefore, the surface 10a of the strip member 10A the metal foil 10 to which the coating liquid 5 is applied, the lower surface of the strip element 10A the metal foil 10 ,

In the present invention, the surface 10a of the strip member 10A the metal foil 10 which is to be coated by the coating liquid 5, not on the lower surface of the strip member 10A the metal foil 10 limited. For example, it may be the top surface of the strip element 10A the metal foil 10 or the upper and lower surfaces of the strip element 10A be the metal foil 10.

The coating of the coating liquid 5 takes place when the strip element 10A the metal foil 10 between the gravure roll 21 and the backup roller 23 passes. In other words, the coating liquid 5 in the tub 26 adheres to the circumferential surface 21a of the gravure roll when the gravure roll 21 rotates 21 on and the coating liquid 5 gets into every cell 22 , Then the excess coating liquid 5 , which on the peripheral surface 21a of the gravure roll 21 adheres, stripped with the squeegee (scraper) 24. Thereafter, the peripheral surface 21a of the gravure roll passes 21 with the surface 10a of the strip element 10A the metal foil in contact, and the coating liquid 5 in the cell 22 is applied to the surface 10a of the strip element 10A the metal foil 10 spent. As a result, the carbon fiber layer becomes 11 that spent off coating liquid 5 is formed over the entire surface 10a of the strip element 10A formed of the metal foil 10. Thus, a strip element 12A the coated film 12 in which the carbon fiber layer 11 is formed on the surface 10a of the strip member 10A of the metal foil.

The direction of rotation of the gravure roll 21 is normally in the same direction as the feeding direction F of the strip element 10A the metal foil 10 set. The peripheral speed of the gravure roll 21 is usually set to be equal to the feed rate of the strip element 10A the metal foil 10 is.

The drying oven 28 is arranged, the carbon fiber layer 11, which is formed on the surface 10 a of the strip member 10 A of the metal foil (that is, the carbon fiber layer 11 of the strip member 12A the coated film 12 ), heat and dry to evaporate the solvent 3 that is contained in the carbon fiber layer 11, to cause the carbon fiber layer 11 to remove it.

In the gravure roll 21 the gravure coater 20 is the shape of the cell 22 a cup shape, and it is particularly preferred that the shape of the cell 22 is a shape that is substantially closed around the entire circumference of the cell 22.

In particular, the shape of the cell 22 preferably at least one form selected from the group consisting of a lattice form 22A (see 3A and 3B ), a pyramidal shape 22B (see 4A and 4B ), a hexagonal shape 22C (see 5A and 5B ), and a circular shape 22D (see 6A and 6B ).

The lattice forming cell 22A is formed to be recessed in the truncated-cone-shaped quadrangular pyramid shape as in FIGS 3A and 3B shown.

The pyramidal molding cell 22B is formed to be recessed in the quadrangular pyramid shape as in FIGS 4A and 4B shown.

The hexagonal molding cell 22C is formed to be recessed in the frusto-conical hexagonal pyramid shape as in FIGS 5A and 5B shown.

The circular molding cell 22D is formed to be recessed in the truncated cone shape as in FIGS 6A and 6B shown.

Further, the shape of the bottom surface 22b of the cell 22 (For example, a grid shape, a pyramid shape, a hexagonal shape, a circular shape) not limited. For example, it can be a flat shape as in 7A be shown to be a concave-curved shape (eg, a concave spherical shape), as shown in Figure 7B, a concave conical shape (eg, a concave pyramidal shape, a concave cone shape), as in 7C shown, or a form in which at least two of these forms are combined.

Further, in this embodiment, it is preferable that the cell 22 has a shape in which the perimeter of the cell 22 is completely closed over the entire circumference, however, the present invention is not limited thereto. As in 8th As shown, the mold may be formed such that the small communication terminals 22c that make up a part of the coating liquid 5 in the cell 22, in the neighboring cells 22 in part of the inner peripheral side surfaces 22a of the cell 22 are formed.

It is preferable that the size of the cell 22 big enough so that the carbon fiber 1 with average fiber length in the cell 22 in a state substantially parallel to the opening area of the cell 22 can get and that the carbon fiber 1 with average fiber length in the cell 22 is included 360 degrees in the cell 22 in the inner circumferential direction of the cell 22 can be turned. In particular, it is preferred that the diameter W of the circle N (in particular circle N, which is in the opening peripheral edge 22d of the cell 22 inscribed) in the mouth of the cell 22 inscribed, to 1.2 times or more of the average fiber length of the carbon fiber 1 is set.

In the 3A . 4A and 5A is the circle N, which is in the mouth of the cell 22 inscribed, indicated by the two-dot dashed line. In 6A fits the circle N, which is in the mouth of the cell 22 inscribed to the opening peripheral edge 22d of the cell 22 ,

As described above, the shape of the cell 22 a cup shape and the diameter W of the circle N, in the mouth of the cell 22 is set to 1.2 times or more the average fiber length of the carbon fiber 1. For this reason, when the coating liquid passes 5 in the tub 26 on the peripheral surface 21a of the gravure roll 21 attached (so if the peripheral surface 21a of the gravure roll 21 is immersed in the coating liquid 5 in the tub 26), the coating liquid 5 into the cell 22 so that the fiber directions of the carbon fibers 1 in the coating liquid 5 in the inner circumferential direction of the cell 22 are randomly distributed. The carbon fiber 1 in the coating liquid 5 that in the cell 22 may be contained in the inner circumferential direction of the cell 22 rotate. In this state becomes when turning gravure roll 21 the coating liquid 5 in the cell 22 on the surface 10a of the strip element 10A the metal foil 10 spent or transferred. As a result, the carbon fiber layer becomes 11 on the surface 10a of the strip element 10A formed of the metal foil 10 so that the fiber directions of the carbon fibers 1 in the surface 10a of the strip member 10A the metal foil 10 distributed randomly or randomly.

On the other hand, in cases where the shape of the cell 22 is not a cup shape, but of the oblique line type (not shown), as the shape of the cell 22 well known, the coating liquid 5 when the coating liquid 5 in the tub 25 on the peripheral surface 21a of the gravure roll 21 attached, probably in the cell 22 so that the fiber directions of the carbon fibers 1 in the coating liquid 5 in a direction along the direction of the oblique line of the cell 22 are aligned. In this state, the coating liquid 5 becomes in the cell 22 with rotating gravure roll 21 on the surface 10a of the strip element 10A the metal foil 10 spent or transferred. As a result, the fiber directions of the carbon fibers become 1 in the surface 10a of the strip element 10A the metal foil 10 not statistically distributed, but likely to be unidirectional. Therefore, the shape of the cell 22 must be a cup shape and not a shape of an oblique line.

The upper limit of the diameter W of the circle N, that in the mouth of the cell 22 is not limited, but is for example 2500 microns.

In cases where the shape of the opening peripheral edge 22d of the cell 22 is a square shape (eg, a lattice shape 22A, a pyramid shape 22B), it is preferable that the diameter W of the mouth shape of the cell 22 inscribed circle is larger than that when the shape of the cell 22 a hexagonal shape 22C or a circular shape 22D. In particular, it is particularly preferred that it be 1.5 times or more the average fiber length of the carbon fiber 1 is.

In a state after the carbon fiber layer 11 on the surface 10a of the strip element 10A the metal foil 10 through the gravure roll 21 was formed and before the strip element 10A the metal foil 10 (the strip member 12A of the coated film 12 ) enters the drying oven 28 (ie before step S1a of removing the solvent 3 from the carbon fiber layer 11 ), it is preferable that the surface of the carbon fiber layer 11 no leveling processing is performed to smooth the surface.

The leveling processing means a processing for smoothing the surface of the carbon fiber layer 11 by sliding the surface of the carbon fiber layer 11 with the end edge peripheral portion of a doctor leveling member by feeding the strip member 10A of the metal foil 10 in the feeding direction F against the leveling-out member in a state where the end edge peripheral portion of the leveling-out member (eg, leveling plate) is the surface of the carbon fiber layer 11 touched in the direction that the feed direction F of the strip element 10A the metal foil 10 crosses (eg, vertical direction).

When this coating leveling processing is applied to the surface of the carbon fiber layer 11 is applied, the fiber directions of the carbon fibers tend 1 in the carbon fiber layer 11, to be aligned in the direction along the end edge peripheral portion of the leveling element. Therefore, it is preferable not to apply the leveling-off processing to the surface of the carbon fiber layer, if possible 11 apply. In cases where the leveling processing is not applied to the surface of the carbon fiber layer 11 is applied, it is possible the fiber direction of the carbon fiber 1 in the carbon fiber layer 11 in the surface 10a of the strip member 10A of the metal foil 10 reliably maintain statistically distributed. This makes it possible to determine the physical properties of the composite material 17 in the plane direction of the composite material reliably compensate.

The carbon fiber 1 can be used if it is a fibrous carbon particle. In particular, for example, one or two or more blended carbon fibers selected from the group consisting of PAN (polyacrylonitrile) -based carbon fiber, pitch-based carbon fiber, and carbon nanofiber (eg, vapor phase growth carbon fiber, or carbon nanotube) may be used.

Among a PAN-based carbon fiber and a pitch-based carbon fiber, it is particularly preferable to use a pitch-based carbon fiber. The reason is that the thermal conductivity of the pitch-based carbon fiber in the fiber direction is larger than that of the PAN-based carbon fiber, so that a composite material 17 can be obtained with higher thermal conductivity.

The length of the carbon fiber 1 is not limited, and it is particularly preferred that the average fiber length of the carbon fiber 1 1 mm or less. The reason for this is that the carbon fiber layer 11 on the surface 10a of the strip member 10A of the metal foil 10 can be formed so that the fiber directions of the carbon fibers 1 in the surface 10a of the strip element 10A the metal foil 10 be reliably distributed randomly. This makes it possible to determine the physical properties of the composite material 17 level more reliably in the plane direction.

The lower limit of the length of the carbon fiber 1 is not limited. Usually, the lower limit of the average fiber length is the carbon fiber 1 10 microns.

The fiber diameter of the carbon fiber 1 is not limited. The average fiber diameter of the carbon fiber 1 is, for example, 0.1 nm to 20 μm. In cases where the carbon fiber 1 is a PAN-based carbon fiber or a pitch-based carbon fiber is the carbon fiber 1 For example, a short fiber or a ground fiber and its average fiber diameter is, for example, 5 μm to 15 μm. In cases where the carbon fiber 1 is a vapor phase growth nano carbon fiber, the average fiber diameter is the carbon fiber 1 for example, 0.1 nm to 20 μm.

The binder 2 is used to apply an adhesive force to the carbon fiber 1 to the surface 10a of the strip member 10A of the metal foil 10 to exercise, thereby the carbon fiber 1 in the carbon fiber layer 11, from the surface 10a of the strip member 10A the metal foil 10 fall off, and is usually formed of a resin.

Further, the binder becomes 2 when heated, presumably a sintered residue or an amorphous carbide of an inorganic material, and they become a factor for reducing the thermal conductivity of the composite material 17 as the residue of the binder 2 , For this reason, it is preferable to use a binder 2 to use that at a temperature of 200 ° C to 450 ° C in a non-oxidizing gas envelope does not carbonize, but by sublimation or decomposition disappears. As such a binder, an acryl-based resin, polyethylene glycol-based resin, a butyl rubber resin, a phenolic resin, a cellulose-based resin or the like is suitably used. These binders 2 are generally in solid form at ambient temperature.

The solvent 3 is preferably a solvent which is the binder 2 dissolves at room temperature. As the solvent 2, it is preferable to use water, an alcohol-based solvent, a hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, etc.

The coating liquid 5 preferably contains the carbon fiber 1 and the binder 2 in a mass ratio of 75:25 to 99.5: 0.5. In this case, the carbon fiber can 1 reliably on the surface 10a of the strip member 10A of the metal foil in step S1 of obtaining the coated film 12 and in step S31 of removing the binder 2 the binder 2 can be reliably removed and removed. It is particularly preferred that the coating liquid 5 the carbon fiber 1 and the binder 2 in a mass ratio of 80:20 to 99: 1.

In step S1 of obtaining the coated film 12 it is preferred to use the coating liquid 5 on the surface 10a of the strip element 10A the metal foil 10 so that the coating amount of the carbon fiber 1, in the carbon fiber layer 11 is 40 g / m ² or less. The reason is as follows.

In other words, when the coating liquid 5 on the surface 10a of the strip element 10A the metal foil 10 is applied so that the coating amount of the carbon fiber 1 that is contained in the carbon fiber layer 11 is 40 g / m ² or less in step S3 of the integral sintering of the coated films 12 the metal of the metal foil 10 sufficiently penetrates into almost all of the voids in the carbon fiber layer 11 and both metal foils 10 and 10 on both sides of the carbon fiber layer 11 are arranged sufficiently sintered. This allows the strength (mechanical Strength, etc.) of the composite material 17 are reliably improved. Further, the manufacturing time of the composite material 17 For the sake of brevity, it is particularly preferable that the coating amount of the carbon fiber 1 contained in the carbon fiber layer 11 is 30 g / m ² or less.

It is preferred to use the coating liquid 5 on the surface 10a of the strip element 10A Apply the metal foil, so that the volume of carbon fiber 1 in the obtained composite material 17 less than 50% of the total volume of the composite material 17 is. Hereby, in step S3 of the integral sintering of the coated foils 12, the metal of the metal foil 10 be reliably impregnated in the carbon fiber layer 11, which can reliably sinter the coated films holistically.

Here, in cases where the composite material 17 as the material of the first stress buffer layer 52 of the insulating substrate 50 shown in FIG 15 , is preferably used, the ratio between the volume of the metal foil 10 and the volume of carbon fiber 1 to adjust such that the coefficient of linear expansion of the composite material 17 in the plane direction becomes an intermediate value between the linear expansion coefficient of the ceramic layer 53 of the insulating substrate 50 and the linear expansion coefficient of the wiring layer 51.

Further, in cases where the composite material 18 is used as the material of the second stress buffer layer 54 of the insulating substrate 50, it is preferable that the ratio between the volume of the metal foil 10 and the volume of carbon fibers 1 to adjust such that the coefficient of linear expansion of the composite material 17 in the plane direction becomes an intermediate value between the linear expansion coefficient of the ceramic layer 53 of the insulating substrate 50 and the coefficient of linear expansion of the cooling layer 55.

In cases where the metal foil 10 For example, an aluminum foil, in particular the linear expansion coefficient of the composite material 17 in the plane direction, to an intermediate value (about 10 × 10 ^-6 / K to 16 × 10 ^-6 / K) between the linear expansion coefficient (eg, about 3 × 10 ^-6 / K to 5 × 10 ^-6 / K) Ceramics (aluminum nitride, alumina, silicon carbide, etc.) which is often used as the material of the ceramic layer, and the linear expansion coefficient (about 23 ^× 10 ^-6 / K) of aluminum which is often used as the material of the cooling layer 55; It is preferable to adjust the volume of the carbon fibers 1 to 10% or more and less than 50% in terms of the total volume of the composite material 17 adjust.

The metal foil 10 (the strip element 10A the metal foil 10) is not limited to the material, as long as it can withstand the coating. In particular, the metal foil 10 is preferably an aluminum foil and / or a copper foil. The reason for this is that a composite material 17 having a high thermal conductivity can be reliably obtained.

In the case where the metal foil 10 is an aluminum foil, the material of the aluminum foil is not limited, and an A1000 series aluminum alloy, A3000 series aluminum alloy, A6000 series aluminum alloy, and the like are used. Generally, the material of the aluminum foil is appropriately selected from a variety of types of aluminum materials, so that the physical properties (thermal conductivity, linear expansion coefficient, etc.) of the resulting composite material 17 become desired default values.

In the case where the metal foil 10 is a copper foil, the kind and the material of the copper foil is not limited, and an electrolytic copper foil, a rolled copper foil and the like are used. Generally, the material of the copper foil is suitably selected from a variety of types of copper materials so that the physical properties of the composite 17 to be obtained become desired default values.

The thickness of the metal foil 10 is not limited, and the thickness of the metal foil 10 may be chosen such that the physical properties of the composite material 17 to be obtained become the desired default values.

Here, the thinnest thickness of a commercially available metal foil (aluminum foil, copper foil) is 10 to 6 μm. For this reason, the lower limit of the thickness of the metal foil 10 is particularly preferable against the background that the metal foil 10 is readily available because the lower limit thereof is 6 μm. The upper limit of the thickness of the metal foil 10 is usually 100 μm, and it is particularly preferable that the upper limit is about 50 μm.

The width of the metal foil 10 is not limited and will be according to the use of the composite material 17 set. For example, it is set to 10 mm to 1200 mm.

As in 2 As shown, step S1a of removing the solvent 3 in that the strip element 12A of the coated film 12 through the drying oven 28, as in 2 represented is performed. In other words, when the strip element 12A the coated film 12 through the drying oven 28 gets the carbon fiber layer 11 through the drying oven 28 heated and dried. As a result, the solvent contained in the carbon fiber layer 11 evaporates 3 and becomes from the carbon fiber layer 11 away. Thereafter, the strip member 12A becomes the coated film 12 wound on the winding roll 27b.

The conditions for the removal of the solvent 3 through the drying oven 28 are not limited unless provided in the carbon fiber layer 11 contained solvents 3 evaporated and from the carbon fiber layer 11 can be removed. Normally, drying conditions can be a drying temperature of 60 ° C to 250 ° C and a drying time of 1 minute to 120 minutes as the conditions for removing the solvent 3 be used.

Further, after removal of the solvent 3 , large cavities may occasionally be formed in the carbon fiber layer 11. Therefore, it is possible to increase the bulk density of the carbon fiber layer 11 by pressurizing the carbon fiber layer 11 in the thickness direction with pressure rollers (not shown) to increase.

<Step S2 of forming the laminate 15 >

In the step of forming the laminate 15 , as in 9 is shown, the strip element 12A the coated film 12, which is unwound from the winding roll 27b, cut with a cutting machine 29 in a predetermined shape. This is a variety of coated films 12 , each having a predetermined shape (eg, an approximately rectangular shape) of the strip element 12A the coated film 12 cut out. Then, as in 10 By laminating a plurality of coated films 12, a laminate is formed 15 formed in which the variety of coated films 12 is laminated. Alternatively, although not shown, the strip element 12A the coated film 12 rolled from the winding roll 27b, rolled or rolled to form a laminate 15 to form, in which a variety of coated films 12 is laminated.

The thus formed laminate 15 is used as preform (sintered material).

The lamination number of the coated films 12 is not limited, and is in accordance with the thickness of the desired composite material 17 set. For example, it is set to 5 to 1000 layers.

<Step S3 of the integral sintering of the coated films 12 >

In step S3 of the integral sintering of the coated films 12 , as in 11 As shown, the laminate 15 is disposed in a sintering member 31 of a sintering apparatus (connecting apparatus) 30, for example, a pressure-heat-sintering machine. Then, the sintering device 30 heats the laminate 15 to a predetermined sintering temperature while the laminate 15 in the lamination direction of the coated films 12 is pressurized (ie, the thickness direction of the laminate 15 ) in a given sintering atmosphere to thereby form the laminate 15 to sinter, so the coated films 12 holistically to sinter. The result is a composite material 17 of this embodiment, as in 13 shown.

In this step S3, the laminate 15 pressurized, leaving the carbon fiber layer 11 compressed in its thickness direction. Hereby enters a part of the metal of the metal foil 10 in the carbon fiber layer 11 and flows into fine voids existing in the carbon fiber layer 11 (eg, a gap between the carbon fibers 1 in the carbon fiber layer 11). As a result, the voids will substantially disappear. As a result, the density of the composite material to be obtained 17 to 95% or more of the theoretical density of the composite 17 to be brought.

It is noted that the theoretical density of the composite 17 is the density of the composite 17 in the case where the composite material 17 only from the metal of the metal foil 10 and the carbon fibers 1 is made, and the cavities within the composite material 17 do not exist at all.

As a sintering device 30 For example, a hot press machine (eg, a vacuum hot press machine), a spark plasma sintering machine, or the like is preferably used.

The compression of the laminate 15 takes place, for example, by pressing the laminate 15 with a pair of punches 32 and 32 included in the sintering apparatus 30 are provided.

The sinter gas envelope is preferably a non-oxidizing shell. The non-oxidizing shell comprises an inert gas envelope (for example, a nitrogen gas envelope, an argon gas shell), a vacuum envelope, etc.

The sintering temperature refers to a temperature at which the coated films 12 can be sintered (integrally joined). In particular, the sintering temperature is at a temperature equal to or lower than the melting point of the metal of the metal foil 10 is. In particular, the sintering temperature is preferably at a temperature between the melting point of the metal of the metal foil 10 and a temperature which is lower than the melting point by about 50 ° C, against the background that the coated films 12 can be reliably sintered holistically. In cases where the metal foil 10 For example, if it is an aluminum foil, the sintering temperature is preferably set within the range of 550 ° to 620 °.

The on the laminate 15 applied pressure is not limited, and can be a compressive force to the extent of a slight pressure of the laminate 15 be. Furthermore, the flowability of the metal of the metal foil 10 sometimes improved when the laminate 15 at the time of application of heat to the laminate 15 is pressurized. Therefore, it is particularly preferable to press the laminate 15 with a pressing force to an extent that the metal of the metal foil 10 not by pressing the laminate 15 from the laminate 15 runs or the laminate 15 in a die or mold (not shown) to press, so that the metal of the metal foil 10 not from the laminate 15 flows.

If the coated films 12 in a state where voids between the coated films 12 remain integral sintered, the cavity portion becomes an internal defect of the composite material 17. Therefore, in order to prevent the occurrence of this defect, it is preferable that the laminate 15 in a vacuum atmosphere as a sintering environment and / or to press the laminate 15 in a mold.

In this embodiment, step S3a of removing the binder takes place 2 through the sintering device 30 during the heating of the laminate 15 in step S3 of the integral sintering of the coated films 12 through the sintering device 30 from about room temperature as the initial temperature to the sintering temperature. Step S3a of removing the binder 2 in this case will be described below.

at 12 it is a figure (graph) showing an example of a temperature curve when heating the laminate 15 in step S3 of the integral sintering of the coated films 12 represents.

The temperature range of T1 to T2 (T1 <T2) in the figure is an area where the binder 2 embedded in the carbon fiber layers 11 of the coated films 12 of the laminate 15 disappears by sublimation or decomposition, and is usually 200 ° C to 450 ° C. T3 is the sintering temperature which is higher than T2 (ie T3> T2).

In step S3 of the integral sintering of the coated films 12 when the temperature of the laminate 15 during the heating of the laminate 15 through the sintering device 30, so that the temperature of the laminate 15 from about room temperature to the sintering temperature T3, within the range of T1 to T2, the binder 2 by sublimation or decomposition disappears and is removed from the laminate 15 (in particular, the carbon fiber layer 11 of the coated film 12 the laminate 15).

The time .DELTA.t, during which the temperature of the laminate 15 is within the temperature range of T1 to T2 is not limited, if it is a period of time that is capable of the binder 2 from the laminate 15 to be removed, and according to the temperature rise rate of the laminate 15 by the sintering apparatus 30 , the total amount of the binder 2 that in the laminate 15 is included, the thickness of the laminate 15 (Eg, the lamination number of the coated films 12 ), the sintering environment, etc. are set. Usually, the time is set to 10 minutes or more.

Further, when the temperature of the laminate 15 is within the temperature range of T1 to T2, the time .DELTA.t can be extended by temporarily stopping the temperature rise or moderating the temperature rise rate, whereby the binder 2 can be reliably removed.

As described above, by performing step S3a of removing the binder 2 during the heating of the laminate 15 in step S3 of the integral sintering of the coated films 12 up to the sintering temperature T3, the number of manufacturing steps of the composite material 17 can be easily reduced, which in turn allows easy production of the composite material 17 allows.

It is noted that the present invention does not exclude that step S3a of removing the binder 2 independently of step S3 of the integral sintering (one-piece joining) of the coated films 12 takes place through the sintering device.

In this case, step S3a of removing the binder 2 is preferably carried out after step S2 of forming the laminate 15 and before step S3 of integrally sintering (integrally joining) the coated films 12 , The reason is that the carbon fibers 1 in the carbon fiber layer 11 can be reliably prevented from the surface 10a of the metal foil 10 at the time of forming the laminate 15 drop. Further, in this case, after performing step S3a of removing the binder 2 and prior to performing step S3 of integrally sintering the coated films 12, the laminate 15 to place in a non-oxidizing gas envelope and / or the temperature of the laminate 15 to 300 ° C or less. The reason for this is that the oxidation consumption of the carbon fibers 1 can be reliably suppressed and the oxidation of the aluminum foil can be reliably prevented when the metal foil 10 an aluminum foil is.

In this embodiment, as described above, the coating apparatus for applying the coating liquid 5 to the surface 10a of the strip member 10A of the metal foil is a gravure coater 20, the shape of the cell 22 the gravure roll 21 the gravure coating device 20 is a cup shape, and the diameter W in the mouth of the cell 22 Inscribed circle N is set to 1.2 times or more the average fiber length of the carbon fiber 1. With this, it is possible to form the carbon fiber layer 11 on the surface 10a of the strip member 10A of the metal foil 10 to form so that the fiber directions of the carbon fibers 1 in the surface 10a of the strip element 10A the metal foil 10 be distributed statistically. Therefore, it is possible the physical properties (thermal conductivity, linear expansion coefficient, etc.) of the composite material 17 in the plane direction.

Further, it is unnecessary to control the fiber direction of the carbon fibers 1 in the formation of the laminate 15 to take into account, so that the balance of the physical properties of the composite material 17 in the plane direction can be easily achieved.

In this case, the arrow "P" in 14 the coating direction of the coating liquid 5 on the surface 10a of the strip element 10A the metal foil 10 through the gravure coater 20 at. In this embodiment, the longitudinal direction A of the composite material means 17 a direction parallel to the coating direction P. The width direction B of the composite material 17 means a direction perpendicular to the longitudinal direction A of the composite material 17 in the plane of the composite material 17 , The oblique direction D of the composite material 17 means a direction oblique to the longitudinal direction A of the composite material 17 below 45 ° in the plane of the composite material 17 , The reference character "C" denotes a thickness direction of the composite material 17 , and this thickness direction D coincides with the lamination direction of the coated film 12 match.

As in 14 In the composite material 17 of this embodiment, the physical properties of the composite material are shown 17 in the longitudinal direction A, the physical properties of the composite material 17 in the width direction B, and the physical properties of the composite material 17 in the oblique direction D substantially the same. Therefore, at the in 15 The insulating substrate 50 is formed by forming at least one constituent layer among the plurality of constituent layers 51 to 55 that surrounds the insulating substrate 50 with the composite material 17 form an insulating substrate 50 having a high reliability with respect to temperature changes such as cold / heat cycle. Therefore, it is possible to suppress the occurrence of cracks and chipping of the insulating substrate 50 due to thermal stress.

On the other hand, in cases where the coater is not a gravure coater 20, but a roll coater (eg, a roller coater), a die coater (eg, a die coater), or a squeegee coater (eg, a squeegee), the fiber directions of the carbon fibers become 1 in the surface 10a of the strip element 10A the metal foil 10 slightly aligned in one direction. For this reason, it is very difficult to balance the physical properties of the composite material 17 in the plane direction.

Although one embodiment of the present invention is described above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope without departing from the spirit of the present invention.

In the present invention, the metal foil to which the coating liquid is applied in the step of obtaining the coated film is not limited to the strip member of the metal foil as in the above-mentioned embodiment. For example, it may be a metal foil (for example, a substantially rectangular metal foil having a predetermined longitudinal dimension and width dimension) which is not like a strip member.

Further, in the present invention, it is particularly preferable that the gravure coating apparatus is a direct gravure coating apparatus as shown in the above-mentioned embodiment. However, contrary to the above embodiment, it may be, for example, an offset gravure coater (e.g., an offset gravure coater).

EXAMPLES

Now, concrete examples and comparative examples of the present invention will be described below. It is noted that the present invention is not limited to the examples shown below.

<EXAMPLE 1>

In Example 1, an aluminum-carbon fiber composite material was produced by the following method.

Carbon fibers having an average fiber length of 150 μm and an average fiber diameter of 10 μm (XN-100, manufactured by Nippon Graphite Fiber Co., Ltd.), a 3% by mass aqueous solution of polyethylene oxide (Alcox (Registered Trade Mark) E-45 by Meisei Chemical Industry Co., Ltd.) having an average molecular weight of 700,000 as a binder, an isopropyl alcohol as a solvent, water, a dispersant and a surface conditioner were stirred and mixed to obtain a coating liquid. The mass of the binder contained in the coating liquid was 10% in terms of solid components in terms of the mass of the carbon fibers. The viscosity of the coating liquid was 1000 mPa * s at 25 ° C.

The coating liquid was applied to the entire lower surface of the tape-like strip member of an aluminum foil (its material: A1N30) having a thickness of 20 μm and a width of 500 mm by a gravure coater (more specifically, a direct gravure coater) at a coating speed of 20 m / min. With this, a strip member of a coated film having a carbon fiber layer formed on the lower surface of the aluminum foil strip member was obtained. Then, the solvent was removed from the carbon fiber layer by passing the strip member of the coated film through the drying oven. The coating amount of the carbon fibers contained in the carbon fiber layer after removing the solvent from the carbon fiber layer was 30 g / m ² .

The composition of the gravure coater was as follows.

The mesh number of the peripheral surface of the gravure roll provided in the gravure coater was # 25, the cell shape was a lattice shape, and the diameter of the circle inscribed in the mouth shape of the cell was 1000 μm.

The conditions for removing the solvent through the drying oven were a drying temperature of 180 ° C and a drying time of 2 minutes.

The strip element of the coated film was then cut into a square shape (its size: length 50 mm * width 50 mm). With this, a plurality of square coated films were cut from the stripe member of the coated film. Then, a laminate was formed by laminating 200 layers of the coated films.

Now, the laminate was sintered, that is, the coated films were integrally sintered by applying heat to the laminate at a predetermined sintering temperature while the laminate was pressed in the lamination direction in the vacuum envelope by a spark plasma sintering device as a pressure-sintering machine. Thus, an aluminum-carbon fiber composite material was obtained. The thickness of the composite material was 4 mm.

The sintering conditions used for this sintering were as follows.

The sintering temperature was 550 ° C, the sintering time (sintering time) of the sintering temperature was 3 hours, the temperature rise rate of room temperature was 50 ° C / min, the applied pressure on the laminate was 15 MPa, and the degree of vacuum was 5 Pa ,

Further, in the step of holistically sintering the coated films as described above, the temperature increase was temporarily stopped while heating the laminate from room temperature to the sintering temperature of 550 ° C, and the binder was removed from the laminate. The removal condition of the binder used at this time was as follows.

The heating temperature of the binder-removing laminate was 380 ° C, and the heating time was 30 minutes.

In the resulting composite material, a plurality of aluminum layers formed of the aluminum foils and carbon fiber layers were alternately laminated, further, the aluminum was sufficiently introduced into the carbon fiber layers, almost no voids exist in the carbon fiber layers, and the density of the composite material was 99% of that theoretical density of the composite material.

<EXAMPLE 2>

In Example 2, an aluminum-carbon fiber composite material was produced by the following method.

Carbon fibers having an average fiber length of 200 μm and an average fiber diameter of 10 μm (K223HM manufactured by Mitsubishi Plastics, Inc.), an acrylic-based resin as a binder, a propylene glycol ethyl ether acetate as a solvent, a dispersant, and a surface conditioner The mass of the binder contained in the coating liquid was 20% in terms of solid components in terms of the mass of carbon fibers, and the viscosity of the coating liquid was 700 mPa * s at 25 ° C.

The coating liquid was applied to the entire lower surface of the tape-like strip member of an aluminum foil (its material: A1N30) having a thickness of 20 μm and a width of 280 mm by a gravure coater at a coating speed of 30 m / min. With this, a strip member of a coated film having a carbon fiber layer formed on the lower surface of the aluminum foil strip member was obtained. Then, the solvent was removed from the carbon fiber layer by passing the strip member of the coated film through the drying oven. The coating amount of the carbon fibers contained in the carbon fiber layer after removing the solvent from the carbon fiber layer was 20 g / m ² .

The design of the gravure coater was as follows.

The mesh number of the peripheral surface of the gravure roll provided in the gravure coater was # 30, the cell shape was a pyramidal shape, and the diameter of the circle inscribed in the mouth shape of the cell was 830 μm.

The conditions for removing the solvent through the drying oven were a drying temperature of 170 ° C and a drying time of 1 minute.

The strip element of the coated film was then cut into a square shape (its size: length 50 mm * width 50 mm). With this, a plurality of square coated films were cut from the stripe member of the coated film. Then, a laminate was formed by laminating 200 layers of the coated films.

Now, the laminate was sintered, that is, the coated films were integrally sintered by applying heat to the laminate at a predetermined sintering temperature while the laminate was pressed in the lamination direction in the vacuum envelope by a vacuum hot-pressing machine as a pressure-sintering machine. Thus, an aluminum-carbon fiber composite material was obtained. The thickness of the composite material was 4 mm.

The sintering conditions used for this sintering were as follows.

The sintering temperature was 600 ° C, the sintering time (sintering time) of the sintering temperature was 6 hours, the temperature rise rate of room temperature was 20 ° C / min, the applied pressure on the laminate was 15 MPa, and the degree of vacuum was 5 * 10 ^-1 Pa.

Further, in the step of holistically sintering the coated films as described above, the temperature increasing rate (20 ° C / min) was slower than that in Example 1 (50 ° C / min) and heating the laminate from room temperature to the sintering temperature of 600 ° C, the temperature increase was not temporarily stopped. Nevertheless, the binder was removed from the laminate.

In the resulting composite material, a plurality of aluminum layers formed of the aluminum foils and carbon fiber layers were alternately laminated, further, the aluminum was sufficiently introduced into the carbon fiber layers, almost no voids exist in the carbon fiber layers, and the density of the composite material was 99% of that theoretical density of the composite material.

<Comparative Example 1>

In Comparative Example 1, an aluminum-carbon fiber composite material was produced by the following method.

The same coating liquid as that used in Example 1 was prepared. The coating liquid was applied to the entire lower surface of the tape-like strip member of the aluminum foil (its material: A1N30) having a thickness of 20 μm and a width of 150 mm with a test applicator at 20 m / min. With this, a strip member of a coated film having a carbon fiber layer formed on the lower surface of the aluminum foil strip member was obtained. Then, the solvent was removed from the carbon fiber layer by passing the strip member of the coated film through the drying oven. The coating amount of the carbon fibers contained in the carbon fiber layer after removing the solvent from the carbon fiber layer was 30 g / m ² .

The conditions for removing the solvent through the drying oven were a drying temperature of 100 ° C and a drying time of 30 minutes.

The strip element of the coated film was then cut into a square shape (the size of which was: length 50 mm * width 50 mm). With this, a plurality of square coated films were cut from the stripe member of the coated film. Then, a laminate was formed by laminating 200 layers of the coated films.

Now, the laminate was sintered, that is, the coated films were integrally sintered by applying heat to the laminate at a predetermined sintering temperature while the laminate was pressed in the lamination direction in a vacuum envelope by a spark plasma sintering apparatus as a pressure-sintering machine. Thus, an aluminum-carbon fiber composite material was obtained. The thickness of the composite material was 4 mm.

The sintering conditions and binder removal conditions used for this sintering were the same as those in Example 1 described above.

In the resulting composite material, a plurality of aluminum layers formed of the aluminum foils and carbon fiber layers were alternately laminated, further, the aluminum was sufficiently introduced into the carbon fiber layers, almost no voids existed in the carbon fiber layers, and the density of the composite material was 99% of that theoretical density of the composite material.

<Comparative Example 2>

In Example 2, an aluminum-carbon fiber composite material was obtained by the same production steps and production conditions as those in Comparative Example 1, except that the laminate was formed by laminating 200 layers of the coated films so that the coating directions were alternately perpendicular to each other.

In the resulting composite material, a plurality of aluminum layers formed of the aluminum foils and carbon fiber layers were alternately laminated, further, the aluminum was sufficiently introduced into the carbon fiber layers, almost no voids existed in the carbon fiber layers, and the density of the composite material was 99% of that theoretical density of the composite material.

<Measurement of physical properties>

With regard to the composite materials of Examples 1 and 2 and Comparative Examples 1 and 2, the thermal conductivity and the coefficient of linear expansion were measured. The results are shown in Table 1.
Thermal conductivity (W / (m · K)) Linear expansion coefficient (× 10 ^-6 / K) Presence or absence of flaking A * B * C * D * A * B * C * D * Example 1 280 275 100 279 6 6 22 6 none Ex. 2 248 252 98 250 8th 7 23 8th none Comp. 1 324 146 95 138 4 13 22 18 available Comp. 2 276 279 98 215 6 6 22 10 available *: "A" denotes "A direction", "B" denotes "B direction", "C" denotes "C direction", and "D" denotes "D" direction.

In the columns "thermal conductivity" and "linear expansion coefficient" in Table 1, "A direction", "B direction", "C direction", and "D direction" mean as in 14 shown, the longitudinal direction A, the width direction B, the thickness direction C, and the oblique direction D of the composite material.

As shown in Table 1, in the composite materials of Examples 1 and 2, the thermal conductivities in the A direction, the B direction, and the D direction are substantially the same, and the linear expansion coefficients in the A direction, the B direction, and the D-direction were also about the same. Therefore, it was confirmed that the physical properties (thermal conductivity, linear expansion coefficient) in the plane direction of the composite material of Examples 1 and 2 are substantially uniform.

In the composite material of the comparative example 1 however, the thermal conductivities in the A direction, the B direction, and the D direction differed from each other, and the linear expansion coefficient in the A direction, the B direction, and the D direction were also different. In the composite material of the comparative example 2 For example, the thermal conductivities in the A direction and the B direction were substantially the same, but the thermal conductivity in the D direction was different from the thermal conductivities in the A direction and the B direction. The linear expansion coefficients in the A direction and the B direction were the same, but the linear expansion coefficient in the D direction was different from the linear expansion coefficients in the A direction and the B direction. Therefore it was confirmed that the physical properties (thermal conductivity, linear expansion coefficient) of the composite materials of Comparative Examples 1 and 2 in the plane direction are poor in terms of uniformity.

<Cold Heat Cycle Test>

The following cold / heat cycle tests were performed on the composite materials of the above Examples 1 and 2 and Comparative Examples 1 and 2, respectively.

The composite materials of Examples 1 and 2 and Comparative Examples 1 and 2 were each cut into a square shape (size: length 30 mm * width 30 mm), and a silicon carbide plate (SiC plate) of square shape (size: length 20 mm * width 20 mm * Thickness 1.6 mm) was bonded to each surface by soldering in a laminated state. As a result, joined elements of Examples 1 and 2 and Comparative Examples 1 and 2 were obtained. Then, a cold / heat cycle test was performed at -40 ° C and 80 ° C with 3000 cycles for each element joined.

As a result of this cold / heat cycle test, the joined elements of Examples 1 and 2 did not flake off at the bonding interface. Therefore, it was confirmed that the composite material of Examples 1 and 2 can be suitably used as a material of a constituent layer of an insulating substrate. On the other hand, in the joined elements of Comparative Examples 1 and 2, chipping occurred partly at the bonding interface and further deformations. These results are shown in the column "presence or absence of spalling" in Table 1.

The present application respects the priority of Japanese Patent Application No. 2015-152416 , filed on 4 December 2015, the entire disclosure of which is incorporated by reference in its entirety into this document.

It is noted that the terms and phrases used herein are used for illustration and are not intended to be construed as limiting, and do not eliminate correspondences of features shown and mentioned herein, and allow various modifications that may be made therein of the claimed scope of the present invention.

Although the present invention may be embodied in many different forms, a number of illustrative examples are described herein, with the knowledge that the present disclosure is to be considered as indicating examples of the principles of the invention and these examples are not intended to be construed. to limit the invention to preferred embodiments described herein and / or illustrated herein.

Although embodiments of the invention have been described herein, the present invention is not limited to various preferred embodiments described herein, but includes all embodiments with equivalent elements, modifications, omissions, combinations (eg, aspects of various embodiments), adjustments, and / or modifications as they would be understood by a professional. Limitations in the claims are to be construed broadly based on the language used in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exhaustive. For example, in the present disclosure, the term "preferred" is not exhaustive and means "preferred, but not limited to". In this disclosure, and throughout the pursuit of this application, "means-plus-function" or "step-plus-function" restrictions are only applied where, for a particular claim constraint, all of the following conditions are present in this constraint: a) "Means for" or means for or "step for" or step to be explicitly mentioned; b) a corresponding function is expressly mentioned; and c) structure, material, and actions that support this structure are not mentioned. In this disclosure, and while following this application, the terminology "present invention" or "invention" may be used to refer to one or more aspects of the present disclosure. The language in the present invention or invention should not be construed as improperly identifying or criticizing it, should not be construed as being in all respects across all aspects or embodiments (it being noted that the present invention has a number of aspects and embodiments), and should not be construed as limiting the scope of the application or claims. In this disclosure, and while following this application, the terminology "embodiment" may be used to describe an aspect, feature, method or describe a step, a combination of these, and / or a part of them. In some examples, various embodiments may include overlapping markers. In some examples, various embodiments may include overlapping features. In this disclosure, and while following this case, the following abbreviations may be used: "eg", meaning "for example"; and "BN", as "mind you" means.

Industrial applicability

The present invention can be applied to a method of producing a metal-carbon fiber composite material and a method of manufacturing an insulating substrate.

LIST OF REFERENCE NUMBERS

1

Carbon fiber

2

binder

3

solvent

5

coating liquid

10

metal foil

10A

Strip element of the metal foil

11

Carbon fiber layer

12

coated film

12A

Strip element of the coated film

15

laminate

17

Metal-carbon fiber composite material

20

Gravure coater

21

Gravure roll

22

cell

28

drying oven

30

sintering apparatus

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 5150905 [0008, 0010]
• JP 5145591 [0009, 0010]
• JP 2015152416 [0171]

Claims (7)

A method of producing a metal-carbon fiber composite material, the method comprising the steps of: Obtaining a coated film in which a carbon fiber layer on a surface of a metal foil by applying a coating liquid containing carbon fibers, a binder, and a solvent for the binder in a mixed state, onto the surface of the metal foil with a gravure coater coated with a gravure roll in which a row of cells are formed on a peripheral surface thereof; Forming a laminate in a state where a plurality of coated films are laminated; and integrally joining the coated films by heating the laminate to remove the binder from the laminate, and heating the laminate while pressurizing the laminate in a lamination direction of the coated films, wherein a shape of the cell of the intaglio roll is a cup shape and a diameter of a circle inscribed in a mouth shape of the cell is set at 1.2 times or more an average fiber length of the carbon fibers. A method for producing a metal-carbon fiber composite material according to Claim 1 wherein the step of obtaining the coated film comprises a step of removing the solvent from the carbon fiber layer formed on the surface of the metal film. A method for producing a metal-carbon fiber composite material according to Claim 1 wherein the step of obtaining the coated film comprises a step of removing the solvent from the carbon fiber layer formed on the surface of the metal foil without subjecting the surface of the carbon fiber layer to doctoring processing. A method for producing a metal-carbon fiber composite material according to any one of Claims 1 to 3 wherein, in the step of integrally joining the coated films, the binder is removed from the laminate during heating of the laminate so that a temperature of the laminate increases to a temperature at which the coated films are integrally joined. A method for producing a metal-carbon fiber composite material according to any one of Claims 1 to 4 wherein the shape of the cell is at least one shape selected from the group consisting of a lattice shape, a pyramid shape, a hexagonal shape, and a circular shape. A method for producing a metal-carbon fiber composite material according to any one of Claims 1 to 5 wherein the metal foil is an aluminum foil and / or a copper foil. A method of manufacturing an insulating substrate having a plurality of insulating substrate constituent layers to be integrated in a laminated state, wherein at least one constituent layer of the plurality of constituent layers is made of a metal-carbon fiber composite material, and the composite material by a method of producing the metal Carbon fiber composite material according to any one of Claims 1 to 6 will be produced.

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